cx_ca VIA presentation

Ataur Rahman

Visual Inspection Aided with Acetic Acid (VIA):

A Feasible Approach for Cervical Cancer

Screening in Bangladesh

12th Annual Scientific Conference at ICDDR’B

Dhaka, Bangladesh

9-12 February 2009

Cervical Cancer: Magnitude of the Problem

• Cervical cancer is the third most common cancer

worldwide

• Globally 493,000 new cases identified each year

• 83% of the new cases occur in developing

countries

• India alone reported 132,000 new cases in 2002

• Globally at least 274,000 women die of cervical

cancer each year

sources: Ferlay J et al. Globocan 2002

Cervical Cancer: Bangladesh

• Leading cause of deaths of all cancer deaths among

women

• Population based studies on cervical cancer are rare

• Hospital data suggests that 25% of all cancer deaths

for women are due to cervical cancer

• No screening system available in present health

system

Incidence and mortality rate of ovarian cancer in

Finland, Bangladesh and Sri Lanka

Mortality rate of cancer cervix in Bangladesh, Sri

Lanka, Finland and UK

Normal cervix in naked eye

Natural History of Cervical Cancer: Current Understanding

Normal Cervix

HPV-related Changes

Low-Grade Lesion (mild dysplasia)

High-Grade Lesion (severe dysplasia)

Invasive Cancer

About 60%

regress within

2-3 yrs

HPV Infection

About 15% progress within 3-4 yrs

30% - 70% progress within 10 yrs

Source: PATH 1997

Limitations of Pap Smears for National Screening

Programs

• Pap smear-based programs require complex logistics,

advanced training, and well managed program

implementation for adequate testing to occur.

• These elements are not available outside large cities in

many low-resource settings.

• Even in large cities, quality Pap smears are possible but

ongoing supervision, refresher training and continued

supplies are not adequate.

• Cytology is not viable as a nationally accessible

screening method in many developing countries.

Other Cervical Cancer screening methods

• Visual Inspection aided with acetic acid (VIA)

• Visual Inspection with acetic acid and

magnification (VIAM)

• Cervicography

• Automated Pap smears

• Molecular (HPV/DNA) tests

• Colposcopy

Visual Inspection Aided with Acetic Acid

• Looking at the cervix to detect abnormalities after applying acetic acid

• Acetic acid is used to enhance and “mark” the acetowhite change of a precancerous lesion or actual cancer

Equipment and material needed for VIA

VIA can be performed in any clinical setting where the

followings are available

• Adequate light source to look at the cervix and

examining its details

• Vaginal speculum, swabs and examination gloves

• Table permitting the examiner to insert the speculum

and view the cervix

• Freshly prepared acetic acid (3-5%, vinegar)

Visual Inspection aided with Acetic Acid

Aceto-white lesion with punctation: a pre-cancerous condition

Visual Inspection aided with Acetic-Acid

Aceto-white lesion with punctation: a pre-cancerous condition

Objectives of the study

To calculate the sensitivity, specificity and positive

predictive values of VIA and Pap smear using

colposcopy with biopsy as the reference test.

To evaluate women’s knowledge and attitude

towards cervical cancer and its prevention through

a screening test in study population.

Method and study locations

A cross-sectional population based study compared two

screening systems for cancer cervical

All ever married women attended in one Urban clinic and

resided in two rural locations (‘Modonpur’ and ‘Dhamgor’

Unions) were invited to perform VIA and Pap Smear tests

All VIA or Pap smear positive and every tenth VIA

negative women were sent to a tertiary level hospital for

reference test

Positive for Pap Smear

Low-grade intraepithelial lesion or more which correspond

CIN I to CIN III (including carcinoma in situ)

Abnormal finding which corresponds detection of one or

more of the following lesions:

Aceto-white lesion, White plaques, Ulcer, Cauliflower-like

growth, fungating mass

Outcome measures

Positive for VIA

Reference test was

Colposcopy with biopsy (where indicated)

• Positive for reference test - a low threshold of low-grade squamous intraepithelial

lesion (LGIL)

- a high threshold of high-grade squamous

intraepithelial lesion HGIL

Number of women participated in different stages

Women

- listed as eligible 8036

- Came to health centre for participation 3290

- Went for VIA screening 2954

- Went for Pap smear collection 2724

Women conducted reference test

As they were VIA positive 288

As they were VIA negative 366

As they Pap positive 10

Women conducted gold test 654

Sensitivity and Specificity of VIA

In detecting at least low-grade lesion

95% CI

Sensitivity 68.0% 59 – 76%

Specificity 61.0% 57 – 65%

In detecting high-grade lesion

Sensitivity 79.0% 63 – 90%

Specificity 57.4% 53 – 61%

Sensitivity and Specificity for Pap smear

In detecting at least low-grade lesion

95% CI

Sensitivity 2.0% 0.3 – 8.0%

Specificity 98.4 96.2– 99.6%

Findings from other studies on Pap Smear

• One meta-analysis, combined data from 59 studies of Pap smear estimated

Sensitivity 11 to 99%

Specificity 14 to 97%

• Pap test was unable to achieve concurrently high sensitivity and specificity

• Specificity 90-95% correspond to sensitivity 20-30%

(Fahey MT, 1995)

Inter-observer variation of VIA performance

Level

%

95% CI Background of paramedics

Paramedic 1

Sn

Sp

58.3

64.3

45 -71

57 -71

No formal training, worked as

nurse 10 yrs. in a clinic, used to

do PV

Paramedic 2

Sn

Sp

71.4

71.4

52 – 82

58 - 82

With 18 months formal

training, 7 yrs. working

experience, used to do PV

Paramedic 3

Sn

Sp

65.4

64.2

49 – 83

55 -73

Had 6 weeks training on Pap

Smear, worked 3 yrs. in a

diagnostic clinic, used to do PV

Colposcopy: Reference test

Sample collection for Pap smear using cervical spatula

Scraping cells from

cervix

Making Pap smear slide

Then smearing and

fixing on glass

Pap slide: under microscope

Evaluated by

trained cytologist